The continuing push to produce faster semiconductor devices with lower power consumption has resulted in transistor miniaturization and higher integrated circuit packing densities with each new technology node. For instance, transistors with smaller components allow a higher packing density, which is conducive to faster device operating speeds. Along with shrinking transistor geometries, however, also come a number of challenges to optimize both transistor and integrated circuit (IC) layout design.
One consequence of transistor miniaturization is the construction of smaller gates and source/drain regions in transistors. This, in turn, has caused changes in the composition and construction of the source/drain electrodes used to facilitate device interconnection. To produce a transistor with a sufficiently low series resistance, each transition to a new technology node, has seen the source/drain electrode's composition change from titanium silicide, to cobalt silicide, and now nickel silicide.
Unfortunately a number of problems have been encountered when manufacturing transistors with nickel silicide source/drain electrodes. In some cases, unacceptable numbers of nonfunctional transistors are constructed. In other instances, the source and drain regions punch through the source/drain junction into the semiconductor substrate, resulting in a large leakage current. In still other cases, there is an unacceptably large diode leakage between the source and drain regions and the semiconductor substrate. These problems contribute to the production of unacceptably low yields of transistors that operate within performance specifications.
Accordingly, what is needed in the art is method of manufacturing a semiconductor device with metal silicide source/drain electrodes that do not suffer from the disadvantages associated with conventionally manufactured metal silicide source/drain electrodes, as discussed above.